Charge forming device



Dec. 26, 1933. F. E. ASELTINE CHARGE FORMING DEVICE Filed Jan. 19, 19-31 3 Sheets-Sheet l gmmtoz Fre d Eflse/Zi 7'25 26, 1%3. F. E. ASELTINE ,9

CHARGE FORMING DEVICE Filed Jan.. 19, 1931 3 Sheets-Sheet 2 Fred 514 55127725.

%, S AM Mm Mix Dec. 26, 1933. F. E. ASELTINE CHARGE FORMING DEVICE Filed Jan. 19, 1931 3 Sheets-Sheet 3 m 5 1M w W n M 3m q a w fi h w M m J, F M @w a: NQ\ 0 W M 4, Aw 4H N J Patented Dec. 26, 1933 UNITED srArEs OHARGEFORMING, DEVICE Fred E. Aseltine, Dayton, Ohio, assignor to Delco Products Corporation, ration of Delaware Application January 19, 1931.

Dayton, Ohio, at corpo- Serial N 0. 509,646

' 16 Claims; (01123-521 This invention relates to charge forming devices for internal combustion engines, and more particularly to devices of this typewhich include means for delivering a primary mixture of fuel and air to a plurality of secondary mixing chambers located near the engine intake ports, and in which the primary mixture is mixed with additional air under certain operating conditions. 7

Devices of this character are shown in several earlier applications, for exampleythat of Fred E. Aseltine et al., Serial No. 370,179, filed June 12,

It is the object of the present; invention to provide means for securing a more uniform distribution. of fuel to the engine cylinders.

In certain internal combustion engines, the firing order is so irregular that in earlier devices of this character, it has been founddifiicult to provide means which would supply substantially the same quantity of fuel to, the two-cylinders of a pair which communicate with any intakevport.

For instance, in certain six-cylinder engines a larger number of cylinders fire between thefiring of cylinders 1 and 2 than between the firing of cylinders 2 and 1. In earlier forms of this device whenjemployed with an engine of this particular type, a larger amount of .fuel will be supplied to cylinder 2 than to cylinder 1, because the suction produced in the manifold on the firing of any of the cylinders is transmitted to some extent to the primary mixture conduit, which supplies fuel to cylinders -1 and 2. For this reason during the firing of every other cylindensome fuel .accumulates in the manifold branch which supplies cylinders 1 and 2 with their fuel, charge during the firing of every other engine cylinder. Since a greater number of cylinders fire between the firing of cylinders 1 and 2 than between the firing of cylinders2 and 1, it is obvious that-this accumulation will-be greater at the time'cylinder 2 fires than when cylinder 1 fires; with the-result that too rich a mixture is supplied to cylinder- 2 and tooilean a mixture to cylinder 1. It is the primaryrpurpose of the present invention to provide'means to overcome this difficulty.

It-is also an object of the invention to provide means'for increasing the pressure differential between the endsof the primary mixture conduits to increase the. velocity of flow therethrough, which tends to secure more satisfactory operation of the-engine during acceleration and other operating conditions. I 7

Further objects and advantages of the present invention will beapparent from the following description, reference being had to the accompany-.

ing drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings: Fig. 1 is a plan view of a charge forming device embodying this invention.

Fig. 2 is a section on the line 22 of Fig. 1.

Figs. 3 and 4 are fragmentary views showing modified forms of the invention. I .The device disclosedcomprises an intake manifold 10, having three outlet branches'12, 14 and 16, adapted to communicate with the several intake ports of a six-cylinder engine. Flanges 18 are formedon the manifold branches for securing said manifold to the engine block and a flange 20 is provided at theinlet end of the manifold to which the main be? secured. u V i Since the specific construction of most of the carburetor ,unit is not a part of the presentinvention it will be described only very briefly and reference may be had to the above mencarburetor unit is adaptedto" tioned application for a complete disclosure there- 7 of. The carburetorunit.comprises a housing 22, having a "flange 24Qwhich is secured to the flange 20 by screws '26 when: the carburetor is attached to.the manifold. air inlet coupling 28 admits air to the main housing and a casting 30in which the fuel supply passages are formed, is. secured to thebottom of the housing. A fuel'bowl 32 is provided and is secured imposition by a screw 34, which is screwed into thecasting 30. A constant level of fuel is maintained in the bowl in the usual manner. The

reference numeral 36 indicates oneqof a plurality of primaryniixing chambers, into each of which fuel .is supplied through main and idling fuel nozzles-38 and 40 respectively, air be- 7 ing supplied to all I of the primary mixing chambersfrom aprimary air chamber 42, while the primary mixture formed within the chambers 36,

.fiows through orifices 44 into a plurality of primary mixture conduits 46, controlled by a single throttle valve 48in the'mannerdisclosed in the above application. -These passages 46 communicate with'conduits 50, formed in the manifold .and extending tothe secondary: mixing chambers in the outletvbranches thereof. as shown in Figg'l. Air is admitted through the coupling 28 and is controlled by an air valve 52 normally held in its closed positioniby a spring 54, received between the valve and a flange'56 on a sliding sleeve 58, which is slidablymounte d on a fixed sle ve 60. The opening movement of this valve is controlled by a dashpot comprising a cylinder 62, formed in the casting 30 and a cooperating piston 64 mounted on the lower end of the air valve stem 66.

The air which is admitted through the coupling 28 flows first into a main air chamber 68 and from said chamber through a slot 70 into the chamber 42 and thus to the primary mixing chambers hereinbefore described. Air also flows from the chamber 68 to the air manifold 10 a secondary air passage 71 being provided which connects said chamber with the inlet of the manifold. The flow of air through this passage is controlled by a manually operable valve 72 and a suction operated valve 74 secured to shafts 76 and 78 respectively, these shafts being jour nalled in the main housing. The air valve 72 is operated by means of a connection from the primary throttle 48, the connection being so designed that the primary throttle is permitted to move to a position corresponding to a vehicular speed of approximately 20 to 25 miles per hour on a level, before the valve 72 begins to open. Oi course, the suction operated valve is operated only after the opening movement of the valve 72 begins. r

In addition to the Valves 72 and we, a further means is provided to control the flow of secondary air which is positioned within the manifold itself and this means is also effective to control the degree of suction which is maintained in the various outlet branches of the manifold. This valve is indicated-by the reference character 80 and is slidably received in a cylindrical recess 82, which is formed on top of the middle outlet branch of the manifold, as indicated in Fig. 2, the

' normal position of the valve when the engine is not running being that disclosed in said figure. It will be clear that the valve is normally positioned so that no flow of air is permitted from the manifold inlet to any of the outlet branches, the'valve being held in this position by a spring which'is adapted to be collapsed to various degrees by the engine suction. The valve, as shown in Fig. 2, is in the form of a cylinder having one end closed and at the center is formed a sleeve 84:,which is slidably mounted on a rod 86, eX tending through an orifice 88 in the wall of the cylindrical recess above referred to. The rod 86 is provided with a flange 90thereon and the end of the rod is threaded, a nut 92 being screwed thereon to hold the flange 90 tight against the wall. The rod is in this manner rigidly mounted V in the cylindrical recess 82 and is provided at the opposite end with a nut 94, which limits the movement of the valve 80 in one direction. A coil spring 96 is received between the valveand the manifold wall, as shown in Fig. 2 and holds the valve in its normal inoperative position. A

recess 98 communicates the suction maintained in the outlet branch 14 on the'manifold to the recess 82 and under certain operating conditions, the engine suction is effective to move the valve toward the right in Fig. -2 until the force of the spring 96 is balanced by the effect of said suction.

It will be obvious that with the valve 80 cccupying the position shown in Fig. 2, there will be no communication of the suction from any one manifold branch to any other branch of the manifold, as said valve entirely cuts off communication between the several manifold branches. It will'also be clear thatthis condition will continue as long as the valve 72 in the secondary air passage remains closed, for until this'valvc is opened, the suction in the engine will be ineffective to move the valve 80 from the position shown. As the device is generally constructed, the valve 72 is not designed to open until the vehicle on which the device is used, attains a speed of approximately 25 miles per hour on the level, so that at all speeds lower than this there will be absolutely no communication of the suction from one branch of the manifold to any other branch nor any accumulation of fuel in the passage leading to any engine intake port during the time that any other port is effective.

After the valve 72 is opened, the valve 80 will be opened by the engine suction to a position depending upon the opening of the valve 72, and after the valve 80 begins to open, the suction which is maintained in the manifold branch which is delivering fuel at any one time will be communicated to some extent to the other branches, but to a very much less extent than would be the case if the valve 80 were not provided. I

In view of the fact that a variable number of cylinders fire between the firing of the two cylinders of a pair, for instance, a greater number of cylinders may fire between the firing of cylinders l and 2 than between the firing of cylinders 2 and 1, it will be obvious that the provision of the valve 80 will cause an exactly equal distribution of fuel between the cylinders of any pair at all engine speeds below that at which the valve 80 begins to open, and will tend'to equalize the distribution after the valve begins to open. Since the suction which is communicated to any ineffective branch of the manifold from the one which may be eifective is less When the valve is provided, the accumulation of fuel in the ineffective branch is less on the firing of any cylinder not directly associated with that branch than it would be if the valve were not employed. Therefore, the difference in the amount of fuel accumulated in that manifold branch which supplies cylinders 1 and 2 between the firing of the cylinders 1 and 2 and 2 and 1, is considerably less than with an unobstructed manifold. Obviously, this results in a more nearly equalized charge to the'two cylinders 1 and 2 under all conditions of operation.

It will also be clear that the provision of the valve 80 increases the pressure difierential between the ends of the primary mixture passages and for this reason, increases the velocity of flow therethrough. This results in an immediate delivery of the enriched mixture to the ports on acceleration and, therefore, improves the operation of the engine during the acceleration period. In order to open the valve 80, the

pressure of the spring 96 must be overcome and the pressure differential between the ends of the primary mixture passages is increased to an extent determined by the strength of said spring, 1

which has to be overcome before the valve can be opened.

In the modification disclosed in Fig. 3, the valve 88 is controlled directly by the throttle and opens substantially freely, being retarded only to the extent of the friction of the valve within the passage in which it slides. The valve is positively held closed until the throttle is opened, but at the beginning of the opening movement of the throttle, the means which holds the valveclosed is moved so that the valve may be opened by the suction of the engine to a position determined by the position of the above mentioned means. To accomplish these results, an arm 100 is fixed in any desirable way to the shaft 76 on which the valve 72 is supported. Pivotallyconnected to the free endof said arm is a link 102 pivotally connected. to another link 104, which is slidably' mounted in a bore 106 in the main housing'and at one end is bent, as shown at 108, to extenddownwardly in the rear of the valve 80, which is mounted for sliding movement in a manner similar to that disclosed in the preferred embodiment. As the valve 72 is opened, the train of operating connections above described will move the bent-over portion of the link 106 to the right in-Fig. 3, thus compressing the spring 110, which aids in closing the valve and permitting the valve to be moved to the right until the valve engages the bent-over portion of the link which stops the movement of the valve at a point'determined by the degree of opening of the valve 72. The function of this device need not be further described, as it is substantially the same as that of the device. shown inthe preferred embodiment, the only difference being that in this modification, the position of the valve 80 is positively controlled by the position of the throttle 72 and would remain in any position to which it is moved until the throttle is moved again, notwithstanding the fact that there might be variations in suction within themanifold due to change in load. This is true because there is no means to move the valve'toward its closed position other than thethrottle itself, and the operating linkage extending from the-throttle to the valve 80. r

In the modification shown in Fig. 4, the valve 80 is connected directly to the auxiliary valve 74 to be operated therebythrough the'medium of a link 120, pivotally connected at 122 to the valve '74 and at the opposite end 124 to the valve 80. The operation of this form of the device is substantially the same'as that of the preferred embodiment, as the position of the valve would vary with variations in theengine suction after the throttle 72 is opened, because-the movement of the valve 74 toward closed position on reduction of the engine suction would effect a corresponding movement of the valve 80. 1

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. I

What is claimed is as followsf 1. A charge forming device for internal combustion engines, having in combination, an air manifold having outlet branches adapted to communicate with the intake ports of a multicylinder engine and forming secondary mixing chambers, primary carbureting means for supplying a mixture of fuel and air to said secondary mixing chambers, an air passage admitting air to the manifold, and a'valve at the junction of the manifold inlet with the outlet branches to control the flow from said inlet to the outlet branches.

2. A charge forming device for internal combustion engines, having in combination, an air manifold having outlet branches adapted to communicate with the intake ports of a multicylinchambers, an air passage admitting airto the manifold, and a normally closed valve at the junction of the manifold inlet with. the outlet branches to control ,the flow from saidinlet to" the outlet branches, said valve adapted to be opened by engine suction under'certain operating conditions.

'3. A charge forming device for internal combustion engines, having in combination, an air manifold having outlet branches adapted to communicate with the intake ports of a multicylinder engine and forming secondary mixing chambers, primary carbureting means for,supplying a mixture of fuel and air to said secondary mixing chambers, an air passage admitting airto the manifold, and a normally closed valve at the junction .of. the manifold inlet with the outlet branches to control the flow from said inlet-to the outlet branches, said. valve adapted to be.

opened by engine suction at speeds above a predetermined speed.

4:. A charge formingdevice for multicylinder internal combustion engines, comprising,-a car-,-

buretor unit provided with means for forming a primary mixture of air and fuel, an air manifold associated therewith. having a pluralityv of outlet. branches adapted to communicate with the engine intake ports, means to convey-the primary mixture from the carburetor unit to said outlet branches, and means in said mam-- fold to prevent the suction maintainedin any one of said outlet branches being communicated to the other branches under certain operating conditions. I

I 5. A charge forming device for multicylinder internal combustion engines, comprising, a carburetor unit provided with means for forming, a primary mixture of air. and fuel, an air manifold associated therewith having a plurality of outlet branches adapted to communicate with the engine intake. ports, means to convey the primary mixture from the carburetor unit to said outlet'branches, and means in said manifold to prevent the suction maintained in anyone of said outlet branches being communicated tov the other branches at all speeds belcwafpredetermined speed.

6. A chargeforming' device for-multicylinder internalcombustion engines, comprising, atcarburetor unit provided with means forforming a primary mixture of air and fuel, an air manifold associated-therewith having a plurality of outlet branches adapted to communicate :with the engine intake ports, means to convey the primary mixture from'the carburetor unit to said outlet branches, means in said manifold to prevent the suction maintained in every one of said outlet branches being communicated to the other branches at all speeds below a predetermined speed and to limit the suction so communicated at speeds above said predetermined speed.

'7. A charge forming device for multicylinder internal combustion engines, comprising, a carburetor unit provided with means for forming a primary mixture of air and fuel, an air manifold associated therewith having a plurality of outlet branches adapted to communicate with the engine intake ports, means to convey the '8. A charge forming device for multicylinder. internalcombustion engines, comprising, a. car-.1

'buretorunit provided with means for forming a primary mixture of air and fuel, an air manifold associated therewith having a plurality of outlet branches adapted to communicate with the engine intake ports, means to convey the primary mixture from the carburetor unit to said outlet branches, means in said manifold to prevent the suction maintained in any one of said outlet branches being communicated to the other branches under certain operating conditions. said means comprising a suction operated valve and means for holding the valve closed until a predetermined speed is reached.

9. A charge forming device for internal combustion engines, comprising, a carburetor unit provided with means for forming a primary mixture of air and fuel, an air manifold associated therewith having a single inlet and a plurality of outlet branches adapted to communicate with the engine intake ports, means to convey the primary mixture from the carburetor unit to said outlet branches and means in said manifold to prevent the suction maintained in any one of said outlet branches being communicated to the other branches under certain operating conditions, said means comprising an automatic valve located at the point of connection of the manifold inlet with the outlet branches.

10. An intake manifold for a' multicylinder internal combustion engine having a plurality of intake ports, comprising a single intake passage communicating with an air inlet port and plurality of outlet branches associated with said intake ports, conduits adapted to supply a mixture of air and fuel to the manifold branches and a valve at the point of connection of the intake passage with the outlet branches.

11. An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, comprising a single intake passage communicating with an air inlet port and plurality of outlet branches associated with said intake ports, conduits adapted to supply a mixture of air and fuel to the manifold branches and a suction operated valve at the point of connection of the intake passage with the outlet branches.

12. An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, comprising a single intake passage communicating with an air inlet port and plurality of outlet branches associated with said intake ports, conduits adapted to supply a mixture of air and fuel to the manifold branches, and a suction operated valve atthe point of connection of the intake passage with the outlet branches.

13. A charge forming device for multicylinder internal combustion engines comprising, a manifold having a plurality of outlet branches associated with the intake ports of the engine and an outlet adapted to admit air to said manifold, a carburetor unit adapted to supply a primary mixture of air and fueltothe said outlet branches, an auxiliary air passage supplying air to the manifold inlet, a manually operated valve in said air passage, a valve in said manifold, adapted to control the flow of air therethrough, and means connected to said manually operated valve for returning the manifold valve to normal position.

14. A charge forming device for multicylinder internal combustion engines, comprising, a manifold having a plurality of outlet branches associated with the intake ports of the engine and an inlet adapted to admit air to said manifold, a carburetor unit adapted to supply a primary mixture of air and fuel to the said outlet branches, an auxiliary air passage supplying air to the manifold inlet, a suction operated valve in the air passage, a valve in the manifold adapted to control the flow of air therethrough, and means connected to said suction operated valve for operating the valve in the manifold.

15. A charge forming device for internal conibustion engines, having in combination, an air manifold having outlet branches adapted to communicate with the intake ports of a multicylinder engine and constituting secondary mixing chambers, a carbureting device associated with said manifold and having primary carbureting means for supplying a primary mixture of fuel and air to said secondary mixing chamber, an air passage admitting air to the manifold and a single suction operated means for controlling intercommunication between the various outlet branches of said manifold.

16. A charge forming device for internal combustion engines, having in combination, an air .n'ianifold having outlet branches adapted to communicate with the intake ports of a multicylinder engine and constituting secondary mixing chambers, a carbureting device associated with said manifold and having primary carbureting means for supplying a primary mixture of fuel and air to said secondary mixing chamber, an air passage admitting air to the manifold and a spring closed suction operated valve for controlling intercommunication between the various outlet branches of said manifold.

FRED E. ASELTINE.

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